Flipbooks not showing on pages

Hi

I’m testing Real3D flipbook to see if worth buying the pro version.

When I preview the flipbook its shows fine but when I try to add to an existing page (using shortcode) or view the flipbook page nothing shows: https://modernclassicbikes.co.uk/flipbook/modern-classic-motorcycle-news-issue-38/

I rest the permalinks to see if that was an issue but didnt solve it

Its not the theme as I switched themes and still not showing

The page I need help with: [log in to see the link]